<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>session</title>
</head>
<body>
    <% if (username) { %>  
        <h1>欢迎<%= username %> 登录</h1>
        <a href="/logout">退出</a>
    <% } else { %>
        <a href="/login">尚未登录，点击登录</a>
    <% } %>
</body>
</html>